1. Field of the Invention
The present invention relates to an axial-position adjustment apparatus for an arm shaft equipped with paper roll support arms in a paper web feed unit, adapted to adjust the axial position of the arm shaft so as to adjust the axial position of a side edge of paper web to fall within a predetermined range.
2. Description of the Related Art
Conventionally, a paper web feed unit of a rotary printing press is loaded with one to three paper rolls. As shown in FIGS. 4 and 5, a paper web feed unit R of a rotary newspaper-printing press includes an arm shaft 01 rotatably supported by frames F1 and F2, and pairs of paper roll support arms A1 and A2 mounted on the arm shaft 01 such that the paired paper roll support arms A1 and A2 face each other with a predetermined interval established therebetween. A paper roll M is supported between end portions of the paper roll support arms A1 and A2.
Center cones C1 and C2 are provided at the corresponding end portions of the paper roll support arms A1 and A2 while facing each other on the same axis. One center cone C1 is provided in an axially fixed condition, whereas the other center cone C2 is provided in an axially movable condition. Conical portions of the center cones C1 and C2 are inserted into opposite end opening portions of a tubular paper core of the paper roll M, thereby rotatably supporting the paper roll M by the paper roll support arms A1 and A2.
Since the diameter of an opening portion of the tubular paper core varies greatly among paper rolls M, the insertion depth of a conical portion of the axially fixed center cone C into the opening portion of the tubular paper core is not constant. The axially protrudable center cone C2 presses the paper roll M toward the axially fixed center cone C1, thereby causing the paper roll M to move toward the center cone C1. Therefore, the position of the paper roll M in the axial direction (in the width direction) varies.
Therefore, a side edge E of the paper roll M thus supported by the paper roll support arms A1 and A2 may shift axially beyond a predetermined range. In order to adjust the axial position of the side edge E to fall within the predetermined range, an arm-shaft axial-position adjustment apparatus (hereinafter called as an xe2x80x9caxial-position adjustment apparatus) K02 is used for axially moving the arm shaft 01 on which the paper roll support arms A1 and A2 are mounted.
Electric devices for controlling a center cone actuator, a tension control brake, and the like are provided on the paper roll support arms A1 and A2. Electricity is supplied to these electric devices from slip ring units S01 and S02 provided separately from each other at the opposite sides of the arm shaft 01.
The above-described conventional axial-position adjustment apparatus K02 is described in, for example, xe2x80x9cNewspaper Printing Handbook,xe2x80x9d edited by The Technical Committee of The Japan Newspaper Publishers and Editors Association, published by The Japan Newspaper Publishers and Editors Association, Apr. 10, 1997, pp. 101-103. As shown in FIG. 5, the axial-position adjustment apparatus K02 is provided at one end portion of the arm shaft 01 in the paper web feed unit R, whereas an arm-shaft-rotating apparatus (hereinafter called a xe2x80x9cshaft-rotating apparatusxe2x80x9d) K01 for imparting an angular displacement to the paper roll support arms A1 and A2 is provided at the other end portion of the arm shaft 01.
The axial-position adjustment apparatus K02 is also described in xe2x80x9cNewspaper Printing,xe2x80x9d edited by The Engineering Committee of The Japan Newspaper Publishers and Editors Association, published by The Japan Newspaper Publishers and Editors Association, Oct. 31, 1980, pp. 65 and 66.
The axial-position adjustment apparatus K02 will be described in detail with reference to FIG. 6. The arm shaft 01 has a diameter-reduced shaft end portion 011, which is integral with the remaining portion of the arm shaft 01 via a step. The arm shaft 01 is rotatably and axially movably supported, via a sleeve 02, in a shaft hole formed in a casing B attached to an unillustrated frame. A male screw 011a is formed on an end part of the shaft end portion 011 located within the casing B.
A sleeve 03 having a radially inward protruding flange 03a is inserted into the shaft hole of the casing B. A slide key provided on the wall of the shaft hole prevents rotation of the sleeve 03 while allowing axial movement of the sleeve 03.
The arm shaft 01 is rotatably inserted into the bore of the sleeve 03; the shaft end portion 011 is inserted into the bore of the radially inward protruding flange 03a; and the end face of the radially inward protruding flange 03a is in contact with the step of the arm shaft 01.
An annular male screw member 04 greater in diameter than the sleeve 03 is bolted to the radially inward protruding flange 03a. The thus-bolted annular male screw member 04 and the radially inward protruding flange 03a are sandwiched between the step of the arm shaft 01 and a nut 05 engaged with the male screw 011a of the shaft end portion 011 of the arm shaft 01, to thereby be axially immovable in relation to the arm shaft 01.
A worm wheel 07 having a female screw 06 formed on its bore is provided within the casing B coaxially with the arm shaft 01 in a rotatable, axially immovable condition, while being engaged with a worm 08 to be rotated.
The annular male screw member 04 is engaged with the female screw 06 of the worm wheel 07.
When the worm 08 engaged with the worm wheel 07 is rotated by a motor 09 (FIG. 4), the female screw 06 of the worm wheel 07 rotates. The annular male member 04, which, together with the sleeve 03, is nonrotatable, converts rotation of the female screw 06 to an axial movement of the annular male member 04, thereby axially moving the arm shaft 01 via the sleeve 03.
Electric devices provided on the paper roll support arms A1 and A2 receive electricity from the slip ring units S01 and S02 provided separately from each other at the opposite sides of the arm shaft 01. Since the axial-position adjustment apparatus K02 is provided at the shaft end portion 011 of the arm shaft 01, whereas the shaft-rotating apparatus K01 is provided at the other end portion of the arm shaft 01, the slip ring unit S01 is provided within a narrow space between the frame F1 and the paper roll support arm A1, and the slip ring unit S02 is provided within a narrow space between the frame F2 and the paper roll support arm A2.
Conventional axial-position adjustment apparatuses such as those described above involve the following problems.
Since the axial-position adjustment apparatus is provided at an end portion of an arm shaft opposite the end portion at which a shaft-rotating apparatus is provided, space for mounting a slip ring unit is limited. Meanwhile, in recent years, demand for high-speed color printing of newspapers has been increasing in newspaper publishing companies. Thus, rotary newspaper-printing presses have been required to provide precision tension control on paper web in order to maintain or enhance printing quality in high-speed printing.
In order to meet the demand, a large number of control devices required for precision tension control on paper web are provided on paper roll support arms in a paper web feed unit, thereby increasing the number of wiring lines for electricity supply. Therefore, a slip ring unit for a large number of wiring lines must be mounted. However, such a slip ring unit requires wide space along the axial direction of the arm shaft, but the conventional axial-position adjustment apparatuses fail to provide such wide space for mounting the slip ring unit.
An object of the present invention is to solve the above-mentioned problem involved in the conventional axial-position adjustment apparatuses and to provide an axial-position adjustment apparatus for an arm shaft equipped with paper roller support arms in a paper web feed unit, allowing installation thereof adjacent to a shaft-rotating apparatus at one end portion of the arm shaft so as to provide ample space for mounting a slip ring unit at the other end portion of the arm shaft.
To achieve the above object, the present invention provides an axial-position adjustment apparatus for an arm shaft equipped with paper roll support arms, the arm shaft being supported rotatably and axially movably on a frame of a paper web feed unit and rotated by means of a shaft-rotating apparatus located at one end portion of the arm shaft.
The axial-position adjustment apparatus comprises a moving member including a screw portion and connected to the arm shaft in such a manner as to be rotatable and axially immovable in relation to the arm shaft; a guide member including a screw portion engaged with the screw portion of the moving member, the guide member being provided in such a manner as to be nonrotatable and axially immovable in relation to the frame; and a drive unit for rotating the moving member, the drive unit comprising, for example, a motor.
Preferably, the moving member and the guide member are provided adjacent to the shaft-rotating apparatus; the drive unit for rotating the moving member is provided on a support member connected to the arm shaft in such a manner as to be rotatable and axially immovable in relation to the arm shaft; and the screw portion of the moving member and the screw portion of the guide member are of trapezoidal threads or of a ball screw.
In a rotary printing press, the axial-position adjustment apparatus for an arm shaft is adapted to adjust the axial position of a side edge of paper web.
When a side edge of paper web running and being fed from a paper roll shifts axially beyond a predetermined range, the motor receives a rotation signal that is output on the basis of a signal from a detector, and starts rotating in such a direction as to move the side edge in a direction opposite the shift. The motor continues rotating until the side edge position is restored to within the predetermined range. Subsequently, when the detector detects that the side edge position falls within the predetermined range, the output of the rotation signal stops, and thus the motor stops rotating.
Rotation of the motor causes the screw portion of the moving member to rotate, whereby the moving member moves in the axial direction. Axial movement of the moving member is transmitted to the arm shaft independent of rotation of the arm shaft, thereby moving the roll paper support arms; i.e., the paper roll, and thus adjusting the position of the side edge of paper web accordingly.
According to the present invention, the axial-position adjustment apparatus for an arm shaft is provided adjacent to the shaft-rotating apparatus at one end portion of the arm shaft, thereby providing ample space for mounting a slip ring unit at the other end portion of the arm shaft and thus enabling installation of a slip ring unit having a large number of wiring lines. Therefore, a large number of control devices can be provided on paper roll support arms in a paper web feed unit in order to carry out precision tension control on paper web for maintaining or enhancing printing quality, thereby enabling implementation of a rotary printing press capable of performing high-quality, high-speed color printing.